The former landfill site at Ravensthorpe is not a particularly friendly environment for construction, but it is a brownfield site that won't trigger the NIMBYs in the same way some of the HS2 locations have.
The complexity of this construction in 2025 does put into perspective how remarkable some of the work done back in the 19th century was. Of course labour was cheaper and there wasn't much care given to safety of the workforce, but it's still mind boggling what was achieved with nothing like the technology available today.